Many light sources with distinct waveforms exist today that provide for multiple uses. Such light sources include artificially powered electrical lighting devices which provide general illumination. Electrically powered artificial lighting has become ubiquitous in modern society. Electrical lighting devices are commonly deployed, for example, in homes, buildings of commercial and other enterprise establishments, as well as in various outdoor settings. Typical luminaires generally have been single purpose devices, e.g. to just provide light output of a character (e.g. color, intensity, and/or distribution) to provide artificial general illumination of a particular area or space.
Another such light source includes displays or display like devices that provide light output representing a visible image. Recently, there have been proposals to combine some degree of display capability with lighting functionalities. The Fraunhofer Institute, for example, has demonstrated lighting equipment using luminous tiles, each having a matrix of red (R) LEDs, green (G), blue (B) LEDs and white (W) LEDs as well as a diffuser film to process light from the various LEDs. The LEDs of the system were driven to simulate or mimic the effects of clouds moving across the sky. Although use of displays allows for variations in appearance that some may find pleasing, the displays or display-like devices are optimized for image output and do not provide particularly good illumination for general lighting applications. There have also been proposals to add controlled lighting devices to televisions sets. Other proposals suggest a lightbulb like device that can serve alternately as an illumination light source and as a projector.
Combining display and illumination functions into a single device, however, leads to other problems such as a flicker. A flicker is interference between two light sources. It is an unpleasant effect caused by poorly considered luminaire design. Flicker usually causes discomforts such as headache, fatigue, dizziness and nausea to humans. Flicker tends to become more problematic for display-illumination integrated device since there are two systems involved in such a device. Lacking consideration of harmonically presenting both display image and illumination results in annoying flicker. Thus there is a need for technical improvements in display-illumination integrated device to control the flicker.